The worldwide increase in terrorist activity has required consideration of a range of possible targets, and methods to reduce the likelihood of success of terrorist attacks on the targets. One terrorist-attack scenario is an attack on an aircraft or other object by an infrared-guided missile. Man-portable infrared-guided missile systems are widely available throughout the world, at relatively low cost. In such an attack, the seeker of the guidance system of the missile acquires a heat source of the aircraft, typically associated with the main propulsion engines. The missile is fired and guided to the target by the large infrared signature of the heat source.
An aircraft is particularly vulnerable to such an attack during takeoff and landing, when it is flying at low altitude and relatively slowly. The area within the airport security perimeter of an airport is usually secure. However, a terrorist may fire an infrared-guided missile at the aircraft from a hidden location several miles outside the airport security perimeter but near the takeoff flight path or the landing glide path. The seeker of the missile is typically sufficiently sensitive that it can acquire and home on the aircraft heat source from such distances. It is difficult for the aircraft to identify the missile threat, even if the aircraft has an infrared-source detector on board. There are many other infrared sources, such as factories and fires, present and visible during the low-level flight of takeoff and landing. Additionally, it is difficult for the aircraft to take evasive action when it is flying at low altitude and slowly, as occurs during takeoff and landing.
To protect against such attacks, either in low-level or high-level flight, many military aircraft carry flares that may be deployed if an infrared threat is sensed. The deployed flares create an alternative target to draw the attention of the seeker away from the aircraft. The use of flares for civilian aircraft such as commercial transport aircraft is not generally feasible for at least three reasons. First, the flares are normally deployed only when a threat is sensed. The aircraft therefore must carry an infrared threat warning system, which is expensive and not always reliable in situations where there are many nearby heat sources. Second, civilian aircraft typically operate from airports that are much less controlled than are military airfields, and are therefore at greater risk from terrorist attack, requiring a heavy use of flares. Third, the use of countermeasures such as flares on a widespread scale is not socially acceptable for most civilian locations such as airports in and near large cities, because the flares draw too much attention of persons on the ground and because of the debris of the flares.
There is a need for an approach for protecting objects such as civilian aircraft from attack by infrared-guided missiles. Similar needs exist for other types of objects as well. The present invention fulfills this need, and further provides related advantages.